Booking of two dobblerooms (4 persons) in T3, PEK in advance?

We will arrive at the Capital International Airport on Dec. 20, 2015 at 13:05 in Terminal 3. We have 11 hours before our next flight to Auckland (NZ). Where and how do we book 2 dobblerooms in advance? And again for our return from Auckland to Beijing where we arrive at 04:30 on Jan. 2, 2016.?

Thank you.

Yours sincerely,
Marianne Kjoeller
Phone: 0045 26246023